Space filter. 
We use the space filter \(M_{\text{space}}\)  for CIFAR-10, CelebA [1]} and FFHQ [2]}, since they have an obvious spatial distribution characteristics. \(M_{\text{space}}\)  is calculated from the mean of the datasets as shown in Section 4.3 of the main paper.
Empirically, we find out that it is better to normalize the space filter to guarantee the stability. Concretely, we apply the following normalized space filter
\(\hat{M}_{\text{space}}(c,h,w) \leftarrow \frac{1}{3}\Big (2\frac{M_{\text{space}}(c,h,w)}{\max _{c,h,w}M_{\text{space}}(c,h,w)}+1 \Big ).\) 
